Guichón Formation

The Guichón Formation is a Late Cretaceous geologic formation of the Paysandú Group in Uruguay. Dinosaur remains are among the fossils that have been recovered from the formation.

Description
The Guichón Formation comprises mainly pink-greyish to reddish sandstones, which contain moderate to well-sorted, subrounded, fine to medium-sized grains in a pelitic matrix. These sandstones (which compositionally are feldspathic wackes) are either massive or may instead exhibit parallel lamination, cross-lamination and graded bedding. These lithologies were deposited in southwest-trending alluvial–fluvial systems comprising low-sinuosity channels traversing through sandy plains. Subordinate to the already mentioned sandstones are conglomeratic and pelitic lithologies, interpreted as channel-fill and overbank deposits, respectively. It is inferred that the Guichón Formation was deposited in warm, semi-arid climatic conditions. The formation has been correlated to the Puerto Yeruá Formation of northwestern Argentina.

The formation reaches a thickness of more than 100 m in wells perforating the formation. It is overlain by the Mercedes Formation and overlies the Arapey Formation.

Fossil content
The following fossils have been reported from the formation:
 * Udelartitan celeste
 * Uruguaysuchus aznarezi
 * Iguanodontia indet.
 * Theropoda indet.


 * Fossil eggs
 * Sphaerovum sp.